Galileo discovered that like our moon Venus had phases. This supported Copernicus's idea of us not being the center of the universe. If the Sun was in the center,and all the planets go around it, you could see faces on other planets. Galileo saw the faces, so he knew Venus went around the Sun. That also could we did as welland that is what Galileo discovered.
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| A colored Venus |
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| Venus in a dark night |